Amiodarone

General

• Type: Antiarrhythmics
• Dosage Forms: injectable solution, tablet
• Routes of Administration: IV, PO
• Common Trade Names: Cordarone, Pacerone, Nexterone

Adult Dosing

• V-fib/pulseless V-tach
  • Loading dose = 300mg IV bolus followed by 150mg bolus PRN
• Stable V-tach or SVT
  • Loading dose = 150mg IV in 100mL D5W over 10min
    • Follow by infusion of 1mg/min x 6hr; 0.5mg/min thereafter

Special Populations

• Pregnancy Rating: D
• Lactation Risk Categories: Unsafe
• Renal Dosing- no adjustment
  • Adult
  • Pediatric
• Hepatic Dosing- caution and consider dose decrease
  • Adult
  • Pediatric

Indications

• Ventricular and supraventricular arrhythmias
• 1st line for pulseless V-tach/V-fib
• Used for atrial arrhythmias in patients with decreased EF

Contraindications

• Allergy to class/drug
• Iodine or shellfish allergy
• Pregnancy

Adverse Reactions

Amiodarone Adverse Effects

• Bradycardia
• Hypotension with older solvent-based formulation. Uncommon with newer aqueous formulation.
• Prolonged QT
• Thyrotoxicosis
  • Between 5-20% of patients treated with amiodarone have thyrotoxicosis (higher in areas of iodine deficiency)
• Iodine-induced hyperthyroidism
  • It is thought that the iodine load may unmask hyperthyroidism in patients with multinodular goiter and subclinical Graves’ disease
• Drug-induced destructive thyroiditis
  • More commonly, the cytotoxic effects of amiodarone destroy thyroid cells, resulting in a release of preformed hormone.
• Amiodarone pulmonary toxicity
• Hyperpigmentation rash
  

Pharmacology

• Half-life: 58 days
• Metabolism: Liver extensively
• Excretion: Bile primarily

Mechanism of Action

• Class III - Inhibits potassium channels
  • Impairs SA and AV node conduction
  • Decreases automaticity
  • Prolongs refractory period in accessory pathways
• Also has class I & II properties

See Also

• Critical care quick reference